What is the best way to organize an address book between two domains?

Question

Mail for domain

Hello
There is a rather stupid situation on hand, I think many will start laughing and say they are to blame, but it's still a problem. At the moment, there are two domains in the organization - one local located inside the organization, the other imposed from above by the ministry and stuffed with encryption to the very worst. The local domain uses MS Exchange 2007, the ministerial domain uses Zimbra, which works adequately only through the web interface. As a result of the current state of the business process, some users are required to work in the ministry domain (due to working with PD), while the rest of the employees continue to work in the local domain, because it is impossible to enter "left" PCs into the ministerial domain. Domains see each other and, in principle, can communicate within certain limits, but there is no end-to-end registration.
As a result, some people use the address book of the local domain, which we fill out and configure, and some use the ministerial mail, where the address book is missing (it was not filled in, and we personally do not have access to the settings). Addresses of people can be found, but only by full name, which is very inconvenient. In addition, there are only members of the ministerial domain
Tell me if there is any option how to organize a common address book between these two domains so that it:
a) Contains the addresses of both domains
b) updated as automatically as possible
For now, the only option proposed us as a solution was of the form: "Log in from each user of the domain and manually drive in the missing ones for them." Which is ineffective to say the least.

Answer 1

you or incorrectly put a question or do not understand an essence of the address directory.
the address book is the result of a selection from AD, saved as files on YOUR cas-server
and your address book is generated for the domain in which the extension is installed, that is, for yours.
if you can read accounts from a domain higher in the forest, you make a selection of all accounts that have a non-empty e-mail field in the upper domain. For each account in the upper domain, you make the corresponding contact in your domain, in a separate OU (it will be easier to synchronize later). these contacts are already your objects and you can edit them, change the display name, position, phone, address, or whatever else is needed for the local address book. everything except the basic soap.
these created contacts appear in your AK as contacts in the All contacts book
, you do further manipulations with synchronization using the e-mail field, it is unchanged for you.
everything is done easily and gracefully with the help of a power shell.

Answer 2

create in your domain contacts for ministerial addresses in some OU
in your address book - a separate section for them
and according to the scheduler - a script that will read ministerial and update contacts.